Swarm vs Kubernetes decision in Docker - Practice Questions

Challenge - 5 Problems

🧠 Conceptual

intermediate

Choosing between Docker Swarm and Kubernetes for a small project

You have a small web app project with simple scaling needs and limited team experience in container orchestration. Which container orchestration tool is the best fit?

A Docker Swarm, because it is simpler to set up and manage for small teams.

B Kubernetes, because it requires less configuration and is easier for beginners.

C Kubernetes, because it is lightweight and perfect for small projects.

D Docker Swarm, because it has more advanced features than Kubernetes.

💡 Hint

Think about ease of use and team experience for small projects.

Docker Swarm is simpler and faster to set up, making it ideal for small projects and teams new to orchestration. Kubernetes is more complex and better suited for large, complex deployments.

💻 Command Output

intermediate

Output of 'kubectl get nodes' in a single-node Kubernetes cluster

What is the expected output of the command kubectl get nodes on a freshly installed single-node Kubernetes cluster?

Docker

kubectl get nodes

A Error from server (NotFound): nodes "node1" not found

B

NAME           STATUS   ROLES           AGE   VERSION
node1          Ready    control-plane   5m    v1.26.0

C

NAME           STATUS   ROLES           AGE   VERSION
node1          Ready    worker          5m    v1.26.0

D

NAME           STATUS    AGE   VERSION
node1          NotReady  5m    v1.26.0

💡 Hint

Consider the default role assigned to the single node in Kubernetes.

A single-node Kubernetes cluster usually has the node labeled as control-plane and its status as Ready.

🔀 Workflow

advanced

Deploying a multi-service app with Docker Swarm

You want to deploy a multi-service app using Docker Swarm with automatic service discovery and load balancing. Which sequence of commands correctly initializes the swarm and deploys the app using a stack file?

A 1,2,3,4

B 2,1,3,4

C 1,4,2,3

D 4,1,2,3

💡 Hint

Think about the order: initialize swarm, deploy stack, then check services and nodes.

You must first initialize the swarm, then deploy the stack, and finally check the services and nodes status.

❓ Troubleshoot

advanced

Kubernetes pod stuck in Pending state

You deployed a pod in Kubernetes, but it stays in the Pending state indefinitely. What is the most likely cause?

A The pod's YAML file has a syntax error.

B The pod's container image is missing from the registry.

C There are no nodes with enough resources to schedule the pod.

D The Kubernetes API server is down.

💡 Hint

Pending means the pod is waiting to be scheduled on a node.

If no node has enough CPU or memory resources, the pod cannot be scheduled and remains Pending.

✅ Best Practice

expert

Best practice for managing secrets in Kubernetes vs Docker Swarm

Which statement correctly describes the best practice for managing sensitive data (secrets) in Kubernetes compared to Docker Swarm?

A Kubernetes encrypts secrets at rest by default, while Docker Swarm stores secrets unencrypted on disk.

B Kubernetes does not support secrets management, Docker Swarm has built-in secret management.

C Both Kubernetes and Docker Swarm store secrets only in environment variables, which is insecure.

D Docker Swarm encrypts secrets in transit and at rest by default, Kubernetes requires manual encryption setup.

💡 Hint

Consider how each platform handles secret encryption by default.

Docker Swarm encrypts secrets both in transit and at rest by default. Kubernetes stores secrets base64-encoded and requires manual setup for encryption at rest.

Practice

1. Which statement best describes Docker Swarm compared to Kubernetes?

easy

A. Docker Swarm is simpler and faster to set up than Kubernetes.

B. Docker Swarm has more features than Kubernetes.

C. Kubernetes is easier for beginners than Docker Swarm.

D. Kubernetes is only for small projects.

Solution

1. Step 1: Understand Docker Swarm's purpose

   Docker Swarm is designed to be simple and quick to start for container orchestration.

2. Step 2: Compare with Kubernetes features

   Kubernetes offers more advanced features and flexibility but is more complex to set up.

3. Final Answer:

   Docker Swarm is simpler and faster to set up than Kubernetes. -> Option A

4. Quick Check:

   Swarm simplicity = B [OK]

Hint: Swarm is simple; Kubernetes is feature-rich [OK]

Common Mistakes:

• Thinking Kubernetes is easier for beginners
• Believing Swarm has more features
• Assuming Kubernetes is only for small projects

2. Which command initializes a Docker Swarm cluster on the current machine?

easy

A. kubectl create swarm

B. kubectl init cluster

C. docker cluster start

D. docker swarm init

Solution

1. Step 1: Recall Docker Swarm initialization command

   The correct command to start a Swarm cluster is docker swarm init.

2. Step 2: Identify incorrect Kubernetes or invalid commands

   kubectl commands are for Kubernetes, and the others are invalid Docker commands.

3. Final Answer:

   docker swarm init -> Option D

4. Quick Check:

   Swarm init command = A [OK]

Hint: Swarm init uses 'docker swarm init' command [OK]

Common Mistakes:

• Using kubectl commands for Docker Swarm
• Typing incorrect Docker commands
• Confusing cluster start with init

3. Given a project requiring complex scaling and self-healing, which orchestration tool output is expected when checking cluster status?

medium

A. Swarm shows detailed pod logs and events like Kubernetes.

B. Swarm shows limited node details and simple service status.

C. Kubernetes shows detailed pod, node, and event information.

D. Kubernetes shows only basic node count without pod info.

Solution

1. Step 1: Understand Kubernetes status output

   Kubernetes provides detailed information about pods, nodes, and events for complex management.

2. Step 2: Compare with Docker Swarm output

   Swarm offers simpler status info, focusing on nodes and services without detailed pod events.

3. Final Answer:

   Kubernetes shows detailed pod, node, and event information. -> Option C

4. Quick Check:

   Kubernetes detailed status = A [OK]

Hint: Kubernetes status is detailed; Swarm is simpler [OK]

Common Mistakes:

• Assuming Swarm shows pod logs like Kubernetes
• Thinking Kubernetes shows only basic info
• Confusing service status details

4. You tried to join a node to a Docker Swarm cluster but got an error. Which fix is most likely correct?

medium

A. Run 'docker swarm join-token worker' on the manager to get the correct token.

B. Restart the Kubernetes API server.

C. Use 'kubectl join node' command instead.

D. Delete the Docker daemon and reinstall.

Solution

1. Step 1: Identify the cause of join error

   Joining a node to Swarm requires a valid join token from the manager node.

2. Step 2: Correct fix for join token error

   Running docker swarm join-token worker on the manager provides the correct token to join.

3. Final Answer:

   Run 'docker swarm join-token worker' on the manager to get the correct token. -> Option A

4. Quick Check:

   Swarm join token fix = C [OK]

Hint: Get join token from manager with 'docker swarm join-token' [OK]

Common Mistakes:

• Using Kubernetes commands for Docker Swarm
• Restarting unrelated services
• Reinstalling Docker unnecessarily

5. Your team is new to container orchestration and needs to deploy a small app quickly with minimal setup. Which tool should you choose and why?

hard

A. Kubernetes, because it has more features for future growth.

B. Docker Swarm, because it is simpler and faster to start.

C. Kubernetes, because it requires less configuration initially.

D. Docker Swarm, because it supports complex multi-cloud setups better.

Solution

1. Step 1: Analyze team skill and project needs

   The team is new and wants quick deployment with minimal setup, favoring simplicity.

2. Step 2: Match tool choice to requirements

   Docker Swarm is simpler and faster to start, ideal for small projects and beginners.

3. Final Answer:

   Docker Swarm, because it is simpler and faster to start. -> Option B

4. Quick Check:

   Simple quick start = D [OK]

Hint: Choose Swarm for quick, simple setups with new teams [OK]

Common Mistakes:

• Choosing Kubernetes for minimal setup
• Assuming Kubernetes is easier for beginners
• Believing Swarm is better for complex multi-cloud